Colors on the Web

We are frequently asked about colors during presentations on website design. Colors on the web are composed of red, green and blue, where each shade can range in value from 0 to 255, where zero would indicate no red, and 255 would be 100% red. The only confusing part is that these aren’t numbered 0 to 255, but 00 to FF. This numbering system is called hexadecimal, and is efficient for computers.

Sample Web Color Swatches in Hexadecimal

Swatch

Hexadecimal (#RGB)

Decimal (R, G, B)

Percentage (R, G, B)

Color

#000000

0, 0, 0

0%, 0%, 0%

Black

#808080

128, 128, 128

50%, 50%, 50%

Medium Gray

#ffffff

255, 255, 255

100%, 100%, 100%

White

#ff0000

255, 0, 0

100%, 0%, 0%

Pure Red

#00ff00

0, 255, 0

0%, 100%, 0%

Pure Green

#0000ff

0, 0, 255

0%, 0%, 100%

Pure Blue

#00ffff

0, 255, 255

0%, 100%, 100%

Pure Cyan

#ff00ff

255, 0, 255

100%, 0%, 100%

Pure Purple

#ffff00

255, 255,0

100%, 100%, 0%

Pure Yellow

#ffff00

255, 128,0

100%, 50%, 0%

Pure Orange

Counting in Hexadecimal

Counting in hexadecimal is pretty easy. Count 0 to 9 as you would normally. Instead of counting ten, you would count “A”, eleven is “B”, and so on to fifteen, which is “F”. Once you reach “F” you roll over to 10, which in decimal is 16. Which is why we prefix hexadecimal numbers with 0x, so we don’t get confused. So 0x10 is hexadecimal for 16. And, 0xFF is hexadecimal for 255.

The table below counts 0 to 19 in hexadecimal:

Decimal

Hexadecimal

0

0x00

1

0x01

2

0x02

3

0x03

4

0x04

5

0x05

6

0x06

7

0x07

8

0x08

9

0x09

Decimal

Hexadecimal

10

0x0a

11

0x0b

12

0x0c

13

0x0d

14

0x0e

15

0x0f

16

0x10

17

0x11

18

0x12

19

0x13

Frequently asked questions about colors on the web:

Q: Should I use upper or lower case?
You can use upper or lower case, but if you want to be cool, use lower case. It’s old school, and goes back to the days of the C programming language.

Q: Why do they use hexadecimal?
Remember the old adage, computers count in zeroes and ones? It’s true, and it’s called binary (versus decimal or hexadecimal), but to make it easier we use hexadecimal. So 0 to 15 in decimal ranges from 0x00 to 0xFF in hexadecimal, which ranges from 0000 to 1111 in binary.

Q: What is CMYK?
CMYK is for Cyan-Magenta-Yellow-Key (black), and is frequently used in printing.